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SubjectRe: [PATCH v3 1/3] gpiolib: convert 'devprop_gpiochip_set_names' to support multiple gpiochip banks per device
On Tue, Jul 27, 2021 at 8:20 AM Sergio Paracuellos
<sergio.paracuellos@gmail.com> wrote:
>
> The default gpiolib-of implementation does not work with the multiple
> gpiochip banks per device structure used for example by the gpio-mt7621
> and gpio-brcmstb drivers. To fix these kind of situations driver code
> is forced to fill the names to avoid the gpiolib code to set names
> repeated along the banks. Instead of continue with that antipattern
> fix the gpiolib core function to get expected behaviour for every
> single situation adding a field 'offset' in the gpiochip structure.
> Doing in this way, we can assume this offset will be zero for normal
> driver code where only one gpiochip bank per device is used but
> can be set explicitly in those drivers that really need more than
> one gpiochip.
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

One minor comment below, then this looks great:
Reviewed-by: Gregory Fong <gregory.0xf0@gmail.com>

> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
> ---
> drivers/gpio/gpiolib.c | 32 +++++++++++++++++++++++++++-----
> include/linux/gpio/driver.h | 4 ++++
> 2 files changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 27c07108496d..84ed4b73fa3e 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -382,10 +382,18 @@ static int devprop_gpiochip_set_names(struct gpio_chip *chip)
> if (count < 0)
> return 0;
>
> - if (count > gdev->ngpio) {
> - dev_warn(&gdev->dev, "gpio-line-names is length %d but should be at most length %d",
> - count, gdev->ngpio);
> - count = gdev->ngpio;
> + /*
> + * When offset is set in the driver side we assume the driver internally
> + * is using more than one gpiochip per the same device. We have to stop
> + * setting friendly names if the specified ones with 'gpio-line-names'
> + * are less than the offset in the device itself. This means all the
> + * lines are not present for every single pin within all the internal
> + * gpiochips.
> + */
> + if (count <= chip->offset) {
> + dev_warn(&gdev->dev, "gpio-line-names too short (length %d) cannot map names for the gpiochip at offset %u\n",

nit: there should be some punctuation after "(length %d)", otherwise
with parentheticals removed it reads as

"gpio-line-names too short cannot map names ..."

but we need to provide a space between these thoughts for clarity. A
comma should be ok:

"gpio-line-names too short (length %d), cannot map names ..."

Best regards,
Gregory

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